The present invention relates to a power saving apparatus for use in peripheral equipment of a computer, and more particularly to a power saving apparatus that selectively controls the supply of power to or the operational state of computer peripheral equipment in order to conserve power.
Generally, peripheral equipment of a computer represents input/output units connected to a computer system. Common examples of such equipment include monitors, printers, CD-ROM's (Compact Disk-Read Only Memory), and plotters. Usually, peripheral equipment cannot be used immediately after the computer system's power supply is turned on since the equipment requires an initial warm-up period before operation can be commenced. Even if the computer system's power is turned off momentarily and is immediately turned back on, the peripheral equipment still requires the full amount of warm up time until it can be operated. Accordingly, whenever the computer system's power is turned on, waiting for the peripheral equipment to warm up can be very inconvenient. To avoid this problem, a user is required to constantly keep the computer system's power on, so that the peripheral equipment is continually supplied with power. However, this precaution has its drawbacks since it produces alot of needless power consumption. This is particularly true with the computer's monitor. Since the monitor typically drives a CRT (Cathode-Ray Tube) i.e. display means, using a high voltage, there is a great deal of needless power consumption which is very wasteful and expensive for the user.
One attempt to solve these problems is disclosed in U.S. Pat. No. 5,059,961 entitled Screen Blanker for a Monitor of a Computer System issued to Cheng. In this effort, image data from the monitor is blanked if them are no key inputs by the user for a predetermined period of time. If the monitor is blanked and the user then inputs a key function, the screen blanking function is inactivated and the user is once again free to use the monitor and have access to the previously displayed images. However, since the monitor is still supplied with most of its normal power requirements during the period of screen blanking, I believe that power savings is minimal. Also, this invention applies only to the monitor. Therefore, other pieces of peripheral equipment used in the system still suffer from the above mentioned disadvantages.
Another attempt at a power saving apparatus is shown in U.S. Pat. No. 5,249,298 entitled Battery-Initiated Touch-Sensitive Power-Up issued to Bolan et al. In this invention, a power-switching device is used to connect and disconnect a computer system's power supply unit from power line connection. This is accomplished by a battery powered circuit which monitors a contact pad, and powers up the computer system when a user touches the contact. However, when the system is powered down, all parts of the system (not just peripheral equipment and monitor) are disconnected from the power supply. Therefore, whenever the computer system's power is turned on, waiting for the unit (and its peripheral equipment) to warm up can be very inconvenient.
In U.S. Pat. No. 5,237,692 entitled Internal Interrupt Controller for a Peripheral Controller issued to Raasch et al., an interrupt controller provides an interrupt register for a peripheral controller and generates an interrupt any time one or more of the devices controlled by the peripheral controller is activated. The peripheral controller enters a low power consumption mode if no interrupts arc detected for a predetermined period of time. When the interrupt controller generates an interrupt, the peripheral controller is activated from a low power mode and services the device(s) which have caused the interrupt. Raasch however, contains no discussion of using such a power saving feature in the computer's monitor. Since the monitor typically requires a high voltage, it is my opinion that the power savings is minimal.